In one conventional power supply, a lamp controller may be provided to supply power to a cold cathode fluorescent lamp (CCFL). The lamp controller may include a feedback circuit to detect lamp current or voltage, and the lamp controller may adjust power to the lamp based on the feedback information. During an ignition period of a typical lamp, the controller supplies high voltage to the lamp until the lamp is ignited, and thereafter, during a normal operating mode, the supply voltage is reduced. The conventional controller identifies whether the lamps are turned on by detecting if lamp current reaches a threshold. If the conventional controller detects the existence of the lamp current in striking period, it causes inverter controller to end the striking (ignition) mode and switch to a normal, steady state operation mode. During this period, there is insufficient of current flowing through the lamp. Thus, the feedback of the current signal may not reach a commended signal level and lamp ignition failure may happen.